The ribosomal subunits of Mycobacterium bovis, M. tuberculosis and M. batteyi will be investigated as a source of antigen to be used to detect delayed hypersensitivity in guinea pigs infected with heterologous and homologous organisms. Emphasis will be placed on isolation of S30 and S16 ribosomal subunits from these organisms since these subunits appear to contain antigens which are both specific and potent. It is known that S16 subunits of ribosomes of BCG bacilli contain 5 proteins as depicted by electrophoretic analysis and attempts will be made to obtain each of these in sufficient quantities to enable us to employ them as skin test agents. Similar work will be done with proteins from S16 subunits of M. tuberculosis and M. batteyi. Identification of proteins from S30 ribosomal subunits of BCG and of H37Ra organisms has been performed and these "finger prints" show that the number of proteins approximates that found in E. coli S30 subunits. By "lifting" these proteins from the gel it should be possible to obtain sufficient material to perform skin tests in infected animals and to produce antibodies in rabbits which can be used to identify and to isolate the various proteins. BIBLIOGRAPHIC REFERENCES: Smrkovski, L.L., Larson, C.L. and Sogandares-Bernal, F.: Fatal Visceral Leishmaniasis in a Strain of Swiss Mice. J. Parasit. 60(4):718-719, 1974. Baker, M.B., Larson, C.L., Ushijima, R.N. andAnderson, F.D.: Resistance of female mice to vaginal infection induced by Herpesvirus hominis Type 2: Effects of immunization with Mycobacterium bovis, intravenous injection of specific Herpesvirus hominis Type 2 antiserum and a combination of these procedures. Inf. and Immunity 10(6):1230-1234, 1974.